Power-distribution system



Sept. 2, 1930. E. w. SEEGER 1,774,528

' POWER DISTRIBUTION SYSTEM Filed June 7, 1926 2 Sheets-Sheet 1 8m wg/VENTOR. W

A TTOR/VE Y Sept. 2, 1930; E. w. SEEGE R 1,774,528

POWER DISTRIBUTION SYSTEM Filed June 7. 1926 2 Sheets-Sheet 2 8 w gVENTOR. B

ATTORNEY Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE EDWIN W. SEEGER, OF SOUTH MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO CUTLER-J-IAMMER INQ, OF MILWAUKEE, .VISCONSIN, A. CORPORATION OF DELAWARE POWER-DISTRIBUTION SYSTEM Application filed June 7,

This invention relates to power distribution systems, and is particularly applicable to controllers for automatic substations.

One object of the invention is to provide an improved automatic controller for sub stat-ions of the type including a motor generator set.

Another object is to provide a controller of the aforesaid character in which relatively low starting voltage and normal operating voltage are consecutively applied to the motor generator set, and in which a thermal timing relay is employed to interrupt the starting connections if the transfer from starting to running is not made within a predetermined interval.

Another object is to provide a controller of the aforesaid character including means for insuring against opening and reclosure of the running switch upon voltage dips in the supply circuit.

Another object is to provide a controller of the aforesaid character including means for delaying connection of the generator to the distribution circuit upon establishment of the running connections to permit the motor to pull into step.

Another object is to provide a controller of the aforesaid character having improved means for controlling the field of the motor.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing diagrammatically illustrates an embodiment of the invention which will now be described. it being understood that the embodiment illustrated may be modified in certain respects without departing from the spirit and scope of the appended claims.

In the drawing:

Figure 1 diagrammatically illustrates a preferred form of the controller; and

Fig. 2 is a so-called across-the-linc dia gram of the controller illustrated in Fig. 1.

Referring to 1, the same illustrates an automatic substation including a motor generator set, a three phase alternating current supply circuit indicated by lines L L and L and a direct current distribution circuit indicated by lines DC. The motor Serial No. 114,107.

an armature A a series field F and a shunt field F The control means includes a pair of double pole electromagnetic switches 1 and 2 for establishing low voltage starting connections from lines L L and L to the armature A through the medium of compensator windings 3 and 4; and a double pole electromagnetic switch 5 for directly connecting said armature to said lines for running. The field of motor M is controlled by electromag netic switches 7, 8 and 9 and a double pole knife switch 10. Switch 7 is provided with normally closed contacts 7 and normally open contacts 7, the former contacts being provided to connect the field F across a discharge resistance R through the medium of the upper pole of knife switch 10. The field F is also arranged to be connected across resistance R upon opening of knife switch 10 through the medium of auxiliary contacts 10' associated with said knife switch. Switches 8 and 9 are both normally open, and as hereinafter set forth during starting of the motor said switches respond to connect the field F across the terminals of the generator, through the medium of the aforesaid resistance R a second resistance R and an adjustable rheostat RH. Switch 9 is also normally open and is responsive upon establishment of running connections to shunt the resistances R and R An automatic reclosing circuit breaker CB which will be hereinafter more fully described is provided for connecting the generator Gr to the distribution circuit DC.

The automatic control means includes a master switch 12 for controlling a master relay 13 through the medium of an overload device 14 and a timing device 15. Overload device 14 includes a normally closed switch provided with operating windings 14 and 14 connected in different phases of the sup ply circuit, and the timing relay 15 comprises a bimetallic strip normally engaging a stationary contact and having a heating coil 15 associated therewith which is controlled by the master relty l3 and also by normally closed auxiliary contacts F associated with running switch 5. The control means still further includes e i electromagnetic-ally ooerated timing relay l6, voltage responsive relay" Z0 and 21 and a circuit breaker control 2L. liming relay l6 controlle er relay l3 and by the at tacts 0" associated with running d t 1e same 18 also controlled by normally closed auxiin ry contacts S associated with field switch 8. Said timing relay is provid; with normally closed con- "acts l6, normally open contacts 16 and a dash-pot l6, and the latter contacts act thr mgh the nedium or" master relay 13 and auxiiary contacts 5 of running switch 5 to starting" switch Starting control the 7 switch 1 is controlled by master relay 13 and also by auxiliary contacts 2 associated with i switch 2. The running switch 5 is aneed to be connected across the distribui uit through the medium of normally closed auxiliary contacts 2 associated with L i 5 switch 2 and normally open auxily contacts S associated with field switch (l as hereinafter set forth upon establishment oi" running connections a resistance I 'ncluded in ci 'cuit with the operating windi g oi said running switch through opening? of auxiliary contacts 9 associated with field switch 9.

Voltage responsive relay 20 is controlled by i'naster rela l3 and the same controls the and S. The Voltage responfi eld switches sire relay 21 controls the circuit breal-zer rcla 22 through the medium of normally open auxil'ary contacts 9 associated with field switch 9, normally closed contacts 16 associated with timing relay l6 and normally open auriliary contacts 5 associated with running switch 5. Relay 22 in closing provides for opertion of the automatic reclosing circuit breaker, as hereinafter set forth. Also, for purp hereinafter set torch relay 22 is provided r. 1th normally closed auxiliary contacts 22 for controlling a resistance r in the GHQ-l Zing circuit of the Voltage responsive relay 20.

The function anti operation of the aforedescribed contro ler together with the circuit connections therefor will now be more fully described in connection with Fig. Assuming that the parts are in the position shown in lie. 1. upon closure of the master switch l2 switch 13 is energized by a circuit extending" tr in line L through said master switch, through the operating winding of reirough the overload relay e 15 to line L. Running ien position the heater 15 of said running switch and thence through the heater 15 to line L also iimnediately upon closure of switch 15,1 the timing relay 16 is energized by a circuit extendin mom line L through the right 'iand pole or switch 13 igh auxiliary 'OlltttCl'S 5" of running l 5 to and through the operating windof said timing relay and thence circuit for st 'iug swi extending om line L ti igh hand pole of switch 13 tl igh auxiliary contacts o of running si h to and through the o 'ierating wind i 2 of said starti c; switch and thence ugh the contacts ill of the timing relay to lint-L Upoi closurcot itch Z atinpg win ting 1 or starting switch iec ed acres lines L and L through ii closure of starting switches 1 and 2, o-t 'anst r'rier coils 3 and l are contirely, twc oi tlr terminals of the armature A wn it are connected to into mediate taps on said coils, and the other terminal oi? 1e armature s directly connected to line U. T he armaire is thus supplied with low voltage startrig current fro the supply circuit and the motor will. stn t with its field F connected shunt across the step of resistance R 1:. t i tl'iroue h the medium of the upper pole oil the he normally closed conlt uiie switch 10 and to e descii -ed tn "e 4 across the t t c uit exteir operating to fl o1 said volts and then through auxiliary ontac, the Field F to the ri-ht hand terizii'sial of the arma ure A. E len vol of the enerator builds up to a p'i'c 'letern'iined rain. in v 90 responds and in in parallel across the tor. Field switches '7 and 1 rumo -ulnar connect the field F o tCY'O s terminals of the Qcnerator through liel d lower )olc o 'nil RH and lG.

i nicdiate y e timing ic ing of contacts 2. Upon opening of starting switch 2 the running switch 5 is energized by a circuit extending from the lett hand termr nal of the generator through the auxiliary contacts 9 associated. with field switch 9 to and through the operating winding 5 of the running switch and then through the auxiliary contacts 2 associated with starting switch 2 and the auxiliary contacts 8 asso ciated with field switch. 8 to the right hand terminal of the generator. In responding running switch 5 connects the motor M direct ly to lines L L and L and the auxiliary contacts 5 of said running switch connect the operating winding 9 of field switch 9 acr: the terminals of the generator. Field switch 9 then responds and shunts the resistances R and R to strengthen the field of the motor for running and the auxiliary contacts l in opening insert the resistance r in. the energizing circuit of running switch 5. Also upon closure of running switch 5 the auxiliary contacts 5 thereof interrupt the energizing cir cult of heater 15*.

In connection with the foregoing it should be noted that the heater l5 maintained energized as long as the starting connections are maintained. Heater 15- is d nod to eil'ect response of the thermal device 15 after a given interval, and if the running connections are not established within such interval for any reason said thermal device effects deenergization of the master relay 1-5 for interruption of the energizing circuits of the starting switches. lfi urthermorc, it should be noted that variation of the field strength of the motor in the manner above described t'. ds to minimize ine disturbances upon establishment of running connections.

It should also be noted in connection with the foregoing that the running switch 5 is energized by current in the distribution circuit and that in order to deenergize the same it is necessary for the master relay 13 and the voltage relay 20 to open in the order named. A time element is thus introduced to prevent opening and reclosure of the rurming switch 5 upon voltage dips in the supply circuit such as may be caused by short-circuits in the system or by hunting of the motor.

Upon establishment of the atoredescribed running connections voltage relay 21. responds and after a predetermined interval timing relay 16 returns to normal position. Switch 22 is then energized by a circuit extending from the left hand terminal of the generator through the contacts 9 of the field switch 9 to and through the operating winding 22 through the relay 21 and thence through the contacts 16" ot the timing relay and the auxiliary contacts 5 of the running switch to the right hand teiniinal of the generator. Switch 2 in responding acts througi the medium of its contacts 22 to include resistance r in the energizing ci 'cuit of the voltage relay 20. As is well known, upon failure of voltage in the supply circuit the master relay 13 tends to remain in closed position and maintain the voltage relay 2O energized. Since voltage relay 20 controls the running connections it is apparent that unless the same is exceedingly sensitive to voltage drops in the distribution circuit there is a possibility of the running connections being maintained upon restoration of voltage in the supply circuit. The aforementioned resistance T which is controlled by the auxiliary contacts of relay 22 is of such value as to insure opening of the voltage responsive relay upon a slight drop in the voltin the didribution circuit.

As before switch 22 controls the automatic ng circuit breaker GB and,

said circuit breaker is proas shown in F1 l \idcd w th a closing coil 25, the energizing circuit of which is controlled by an overload relay and an auxiliary switch 27. Overload relay 26 is respons *e to load conditions in the distribution circuit, while the switch 2"? is biased to closed position, and upon closure of the circuit breaker the same to ope: position and is held therein by a latch 28. lVhen switch is in open position a resistance ll included in the energizing circuit of the closing coil 25, said resistance being of such value that the same limits current to the operating coil to an amount just sufiicient to hold the circuit breaker in closed position but insufficient to move the same to open position. Latch 28 is provided with a tripping coil 29, the energizing circuit of said coil being controlled by a normally closed auxiliary switch 30. Switch 30 is adapted to open upon closure of the circuit breaker and upon opening of said circuit breaker the same moves to open position against the action 01" a dash-pot 31. The control means for the circuit breaker further includes resistances R and ll said resistances being connected as shown in the drawing for purposes hereinafter set forth.

lVith the parts of the circuit breaker in the position shown in Fig. 2, it will be observed that it the current conditions in the distribution circuit are normal tripping coil 29 will be CBQl' lZGd imme tely upon closh I 4 uro or switch 22 by a circuit extending from a point in one of the lines through the right hv ed pole witch through resistance R thro. said tripping coil and through the auxn switch 30 to a point 33 in the other line. Tripping coil 29 will thus latch 28 for closure of switch 27, and ch in closing excludes the resistance ")erat' coil 25 is then connected points and 33 and the circuit bro. 2r will close and will remain in closed position as long as the current conditions in the distribution circuit are normal.

Upon voltage failure the 'inding 25 will be deenergized and the circuit breaker will reclose only after the dash-pot retarded switch :30 returns to normal position. Upon overload conditions in the distribution circuit re ay 26 opens to interrupt the energizing circuit of winding 25 and the tripping coil 29 will remain unresponsive until the current conditions in the distribution circuit return o normal. Assuming that the circuit breaker been tripped and the parts are in the 'tion shown in Fig. 1, it will be observed when the overload or short-circuit exists vvo paths whereby current may flow from the 32 to the point 33, one of said paths being through the resistance It", coil 29 and itch E50, and the other being through resistances RD and R and the load or short circuit on the distribution circuit. Coil 29 is wound with a low resistance so that a slight variation in the res stance of the load or short-circuit on the distribution circuit will cause a corresponding change of current through coil. Thus, if the load on the dist ibution circuit is of low resistance a large part of the current will be shunted round the coil 29, but as soon as the shortcircuit is removed or the resistance of the circuit increased to a *alue which would not permit excessive current to fiow were the circuit breaker to reclose, enough current will through the coil 29 to avoid tripping of the latch 28 for reclosing of the circuit breaker.

hat I claim and desire to secure by Letters Patent is 1. In combination, an alternating current supply circuit, a direct current distribution circuit, a rotary transformer having a field winding, means for establishing low voltage connections from said supply circuit to said transformer for starting and for thereafter connecting said transformer directly to said supply circuit for running and providing for excitation of said field from the direct current side of said transformer at a reduced voltage upon establishment of starting conucctions and at an increased voltage upon establishment of running connections.

2. In combination, a. supply circuit, a dis tribution circuit, a motor generator set, the motor of said set having a field winding to be supplied with current from the generator of said set, means for selectively establishing low voltage starting connections and full voltage running connections for said motor from said supply circuit, means for connectmg said generator to said distribution circuit after starting of said motor, and means providing for excitation of said field winding by said generator at a reduced voltage upon establishment of starting connections and at an illCI-l .sed voltage upon establishment of running connections.

3. In combination, an alternating current supply circuit, a direct current distribution circuit, a motor generator set, a plurality of electroresponsive switches, certain for establishing low voltage starting connections for the motor of said set from said supply circuit and certain others for establishing full voltage running connections therefor from said supply circuit, and control means for said. switches providing for energization of said former switches from said supply circuit and for energization of the latter by current from the generator of said set.

el. In combination, a supply circuit, a distribution circuit, a motor generator set including a synchronous alternating current motor and a direct current generator, the former having a field winding to be supplied with current from the latter, control means for said motor including means for establishing reduced voltage arn'iature connections for starting and full voltage armature connections for running, and control means for the field winding of said motor including a relay responsive upon establishment of starting connections for said motor to provide for excitation of said field winding from said generator at a reduced voltage and asecond relay responsive upon establishmentof run ning connections for said motor to provide for excitation of said field winding at an increased voltage.

In witness whereof, I have hereunto subscribed my name.

EDWIN W. SEEGER. 

